*::after, *::before {
  box-sizing: border-box;
}

*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  scroll-behavior: smooth;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: #0f1219;
}

nav {
  position: relative;
  display: flex;
  background: #1e232f;
  padding: 10px 0;
}

nav a {
  position: relative;
  text-decoration: none;
  padding: 15px 25px;
  color: #FFF;
  font-weight: 400;
  letter-spacing: .1em;
}

#marker {
  position: absolute;
  bottom: 0;
  height: 100%;
  width: 90px;
  border-bottom: 5px solid #08f9ff;
  background: linear-gradient(0deg, #08f9ff33, transparent);
  transition: .5s;
  pointer-events: none;
  filter: drop-shadow(0 5px 25px #08f9ff);
}